Heatstroke is a medical emergency and often kills. But there are many processes in the body that occur between being exposed to heat and ending up in the ED – and warning signs to look out for too.

Children run through an open fire hydrant to cool off during the kickoff of the 2016 Summer Playstreets Program in the Harlem neighborhood of New York, July, 6, 2016.
AP Photo/Ezra Kaplan
August 7, 2017